Mercury is a naturally occurring element that is known to have a toxic effect on human beings and animals in very low concentrations. Mercury's high toxicity combined with its penchant for bioaccumulation make it of particular concern among heavy metals. In particular, mercury can affect the nervous system, with fetuses, infants, and children being particularly sensitive to the effects of mercury.
There are numerous automated systems for measuring mercury concentrations in a variety of sample types. In many automated mercury analysis systems, a liquid sample may be pushed or drawn from a sample vial to a purge vessel (or a gas-liquid separator), where the mercury is vaporized into a gas for analysis. This method of liquid transfer from the sample vial to the purge vessel has some drawbacks because liquid samples can easily contaminate the transfer line, as well as the purge vessel, resulting in a high bias in subsequent test results.
One system currently on the market purges the liquid sample directly in the test vial, instead of in the purge vessel. However, the sample vials are placed in this system as open containers, and only plugged immediately prior to purging. These open containers are therefore subject to contamination from mercury present in the surrounding air and dust. In low level mercury analysis, preventing contamination of the samples from atmospheric mercury is critical to obtain reliable measurements of mercury in native samples. To mitigate potential contamination, open vial systems are generally operated in a clean room environment, a clean hood, or a hepa-filtered enclosure, all of which add significant costs. In reality, however, these “clean” environment solutions only eliminate particulate mercury in airborne dust, and even air free of particulates still may have a measurable amount of gaseous mercury that can impact results.
Therefore, there exists a need for an improved closed vial analytical system for total mercury analysis that prevents contamination from air and dust, as well as contamination in the transfer line and purge vessel. In order to accomplish this, a septa piercing sampling probe that is non-corrosive to acid is required.